The Research Of Microwave Assisted And Stereospecific Synthetic Methods Of Mannose Oligosaccharide And Their Intermediates

Modern research has shown that, polysaccharides and their conjugates are importantinformation substances, with extremely complex and diverse biological function. They areinvolved in almost all contacting process of the cells. Wherein, mannose oligosaccharide andtheir conjugates have been used in food industrial, pharmaceutical industry and biologicalfield. They are not only having immune activity, but also able to adjust the environment of thegastrointestinal microbial, and adsorb mycotoxins. They play a very important role in HIVinfection and the progression of disease. However, compared to the study of glucosecompounds, there were few studies on them both at home and abroad.In this paper,12kinds of important mannose glycosylation reagents were synthesi-zed using mannose as raw material. They were1,2,3,4,6-penta-O-acetyl-β-D-mannopyr-anose(2),2,3,4,6-tetra-O-acetyl-1-bromide--D-mannopyranose(3),3,4,6-tri-O-acetyl-1,2-O-ethylidene-β-D-mannopyranose(4),1,2-O-ethylidene-β-D-mannopyranose(5),4,6-O-benzylidene-1,2-O-ethylidene-β-D-mannopyranose(6),1,2,3,4,6-penta-O-benzoyl-β-D-m-annopyranose(7),2,3,4,6-tetra-O-benzoyl-β-D-mannopyranose(8),2,3,4,6-tetra-O-benzoyl--D-mannosyl trichloroacetimidate(9),1-O-methyl-2,3,4,6-tetra-O-benzoyl--mannopyranos-e(10),3,4,6-tri-O-acetyl-1,2-O-allyloxyethylidene-β-D-mannopyranose(11),1,2-O-allylo-xyethylidene-β-D-mannopyranose(12),3,4,6-tri-O-benzoyl-1,2-O-allyloxyethylidene-β-D-mannopyranose(13). They are glycosyl donors and receptors in the synthetic processof oligosaccharides and their conjugates, which are the basis of their synthesis, determ-ining the difficulty and production of the synthesis. The specialized research literature-s about them are rarely at present.The research mainly included three aspects. The first aspect, selected optimal syntheticmethods of each compound through comparative study from their existing common syntheticmethods. According to the characteristic of respective reaction, improved and optimized theexisting synthetic methods. After optimization, the yield increased by6.2%,16.8%,4.0%,16.8%,4.3%,3.2%,8.2%,14.1%,0%,2.4%,1.4%,2.3%compared to the related literatures.The second aspect, got the best synthesis process parameters through the new method ofmicrowave assisted synthesis using single factor experiment and orthogonal experiment fromthe above-mentioned improved synthetic methods. Product2,3,4,5,6,7,8,9,11weresynthetized by the microwave assisted synthetic method, and the new methods were notreported. Results showed that compared with the traditional synthetic method, microwaveassisted method could greatly shorten the reaction time, and improve the production rate,while reducing the use of some poisonous and harmful reagents. Their reaction time wasshorten5,11,5,7,6,17,17,8,14times, and the yield increased by5.4%,6.3%,5.3%,4.5%,7.8%,0%,4.0%,3.5%,12.5%. Visible, the new type of microwave assisted synthetic methodis a rapid, high yield, and green synthetic strategy.The third aspect, synthetized2,3,4,6-tetra-O-benzoyl--D-mannosyl trichloroacetimid-ate-（1→3）-[2,3,4,6-tetra-O-benzoyl--D-mannosyl trichloroacetimidate-（1→6）-]1,2-O-ethylidene-β-D-mannopyranose(14) and2,3,4,6-tetra-O-benzoyl--D-mannosyl trichloro -acetimidate-（1→3）-1,2-O-ethylidene-β-D-mannopyranose(15) by the synthetized m-annose glycosylation reagents. Their yields were63.1%and55.2%respectively. Partic-ularly, the synthetic methods of them were simpler compared to the related literatures.It only need control addition amount of TMSOTf and the reaction temperature, avoid-ing the complicated protection and deprotection process.The structure of synthetized14compounds, all got the authentication of MS, IR,1H-NMR.